Present Tense

All verbs (except BE) have one form for all persons except the third person singular.  The third person singular is usually formed by adding s to the root.  After ch, s, sh, x, and z es is added.  Do and go form the third person by adding es.
Words ending in y preceded by a consonant take the es ending after changing y to i.  Notice that the third person singular form of have is has.

Examples:
 

Usages of the present tense:

(1)To express a condition or a general truth that  exists at the moment of speaking and will probably continue for a short time.
Examples:

• He is sick.
• They are angry.
• We are here.
• She seems happy about the news.
   

(2) To express the idea that an activity existed before the moment of speaking and will very likely continue for a long time.
Examples: 
He lives on Wilson Street.
She speaks fluent English.
My mother cooks wonderful cakes.
My country produces a lot of gold.

(3) To express customary action.  Adverbs of frequency (after, frequently, usually, etc) are often used to help express this concept of time.
Examples:

• He often goes to the movies.
• I usually take the bus to work.
• I sometimes sleep late on Sunday.
• She seldom makes a mistake in math.

(4) To express future time. Notice that adverbs indicating future time usually mark the construction.
Examples:

• We meet again next week.  (arranged meeting)
• He leaves for Europe next week. (schedule)
• The movie starts at eight.  (program)
• The train leaves at 7:30 (schedule)
   

(5) To tell a story about a past event where the speaker tries to emphasize the action rather than the time.  This is known as the historic present.
Example:

• John gets up late, gulps a cup of coffee, and rushes to the office.  Now he is in the office.  The telephone rings an rings, and another busy day begins.

Past Tense

The past tense of the regular verb is formed by adding ed, d or t.  The past tense of irregular verbs is formed by an internal vowel change.  The regular (ed) verb is referred to as a weak verb; the irregular verb is referred  to as a strong verb.  The form is the same for all persons, both singular and plural.

An exception is the verb BE:

Usages of the past tense:

(1)To express activities that occurred at a definite time in the past.   The time is specified by definite time words such as yesterday, last night, a year ago.
Examples:

• It rained yesterday.
• He arrived last night.
• They came here a year ago.

(2)To express activities that occurred at an indefinite time in the past.  The point of time is implied or understood from the context.
Examples:

• He went to town.  (a few minutes ago, or considerable time ago)
• He came to see us about his schedule.
• He spoke to the captain about it.

(3)To express activities that occurred in the past over a continuous period of time, but do not continue to the present moment of speaking.
Examples:

• He studied French when he was in high school.
• He worked for the Ford Company a few weeks.
• The student attended school during spring  for five years.